Although it is broadly known to use various types of vibration-damping material for damping or isolating undesirable forces resulting from the operation of hand-held power tools, there remains considerable room for improvements in design, quality and convenience, especially in the area of adapting existing tools to modern exploitation of damping materials as respects location, quantity and adaptability. One prior example of a significant advance in this art in general forms the basis of the U.S. patent to Honsa, 4,648,468. The present invention is an improvement relating to the solution of problems pointed out in that patent.
In the present instance, the tool selected as the background for the improvement may be a typical hand-held powered rotary tool such as a grinder in which a power means such as a motor is contained within the cylindrical cavity of the grinder or tool body for driving an external grinding wheel. The use of the rotary tools, such as heavy-duty grinders and the like is generally considered to be the most damaging to the operator because of the high levels and frequency of vibrations incident to the use of the tool, in many cases resulting in such trauma as vibration white finger disease and carpal tunnel syndrome, both of which are debilitating hand/arm diseases. The improvements effected by the present invention isolate the vibrations as well as damping sounds emitted by operation of the tool. According to the invention, the dimensional relationship between the outer cylindrical surface of the motor housing and the inner cylindrical wall of the cavity is designed in such manner as to afford an annular space into which suitable vibration-damping material is disposed in tightly fitting relation between the cavity and housing so as to isolate or damp vibrations induced by the motor shaft during grinding operations, for example. Thus the transmission of vibratory forces to the hands of the user is significantly reduced, thereby increasing the user's comfort and consequently his productivity.
It is a further feature of the invention to utilize the improvements in existing tools by simple expedients of modifying existing dimensions, particularly to provide the space required to contain the damping material.
The foregoing features and advantages as well as others will appear as the disclosure progresses herein.